fix(hooks): forward all arguments in useAppEvent for custom events

[JonasPfi]

Summary

useAppEvent only forwarded the callback argument for the built-in update event. For every other event (including custom events fired via app.fire(...)) the callback was invoked with no arguments at all.

Root cause

const handler = useCallback(
    (...args: unknown[]) => {
        if (event === 'update') {
            (callback as (dt: number) => void)(args[0] as number);
        } else {
            (callback as () => void)(); // args dropped here
        }
    },
    [callback, event]
);

Only 'update' was special-cased to receive its argument. Every other event was invoked with zero arguments.

Fix

const handler = useCallback(
    (...args: unknown[]) => {
        (callback as (...args: unknown[]) => void)(...args);
    },
    [callback]
);

Forwards all arguments passed to app.fire(...) generically. update, prerender, and postrender continue to work exactly as before, since they simply receive their normal arguments through the same spread.

Testing

Added a new test (should forward all arguments to the callback for custom events) that fires a custom event via app.fire('levelComplete', 3, 1000) and asserts the callback receives both arguments.

I verified this test fails against the old implementation (callback called with no arguments) and passes against the fix, confirming the test actually exercises the bug rather than passing coincidentally.

Note: the existing test file has a comment explaining that built-in input events can't be fired in the null device type used in tests. This doesn't apply here : app.fire(...) is the underlying EventHandler mechanism, not a hardware input source, so it works fine in the test environment.

[changeset-bot]

🦋 Changeset detected

Latest commit: 2ed0d6f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@playcanvas/react	Patch
@playcanvas/blocks	Patch

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commit: 2ed0d6f

[Copilot]

🟢 Approval recommended

The behavioral fix is correct and low-risk, and the added regression test covers the reported failure mode.

Pull request overview

Fixes useAppEvent so event callbacks receive all arguments for non-built-in/custom events (including events fired via app.fire(...)), instead of silently dropping them.

Changes:

• Simplified the internal handler in useAppEvent to forward (...args) directly to the provided callback.
• Added a test that fires a custom event with multiple arguments and asserts the callback receives them.
• Added a changeset to publish the fix as a patch release.

File summaries

File	Description
packages/lib/src/hooks/use-app-event.ts	Removes the update-only special casing and forwards all event arguments to the callback.
packages/lib/src/hooks/use-app-event.test.tsx	Adds a regression test ensuring custom event arguments are forwarded through useAppEvent.
.changeset/deep-towns-attend.md	Declares a patch release for the argument-forwarding fix.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Lite

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